The Heist 6 is a great little entry level multi tool. It has the basics that you will need to keep your ride going. list: 3mm, 4mm, 5mm, 6mm hex keys, torx T25 and Philips Screwdriver. And
at this price you can't go wrong.
14.95
Crank Brothers
m10 multi-tool
Great entry tool with 10 of the most common used tools for on the road adjustments
Price $ 19.95
m17 multi-tool
This tool has just about everything that you need, including a chain breaker.